Boring and hopping up motor.
Boring will ruin the motor. It has a coating, flame spray chrome and nickel type. Not a steel liner. The Flame spray is what allows the motors to be made inexpensively. Some Honda, Weed eaters and such use this technology. Not sure why anyone would want to hop up a Dax or Howell motor, being that they are plenty fast out of the box. Anything faster can not be safe for a bicycle and for sure the police will not like a bicycle going 50 or 60mph through town. Try your best to keep under the radar so that the police will not get mad at us motor assisted bicycle owners..Thanks...Enjoy the ride.